This has been helpful in terms of allowing me to track things. My biggest complaint is that it does not allow you to alter time spent or add sessions. I carry my instrument everywhere and play it throughout the day. I have no way of retroactively adding in those spontaneous sessions. Using the app each time I pick up my instrument would totally disrupt my fun in playing it.
Gertie Floyd about Music Journal Pro - Practice + metronome app to log time and bpm